SNMP Vulnerabilities in Cisco IOS and IOS XE Software

SNMP vulnerabilities are found in Cisco IOS and IOS XE software which could allow attackers to execute code remotely on the affected system. These Simple Network Management Protocol vulnerabilities can either cause to transfer the control of the system in the hands of the attacker or reload the affected system.

All the versions of SNMP (1, 2c or 3) are affected, therefore, the attackers can exploit any version by sending a crafted Simple Network Management Protocol packet to the affected system.

If the attacker knows the SNMP read-only community string, he can exploit SNMP vulnerabilities (SNMP version 2c or earlier). On the other hand, to exploit SNMP version 3, the attacker needs to have user credentials.

The buffer overflow condition in the SNMP subsystem is the cause of SNMP vulnerabilities and Cisco is planning to release software updates in order to address all these vulnerabilities. These vulnerabilities were found during internal testing.

In case your device gets compromised, it will cause your device to reload or generate crashinfo file. In such a situation, you are recommended to contact Cisco Technical Assistance Center, the Cisco team will thoroughly check your device to know whether it is compromised or not.

As a safeguard, administrators should allow only authenticated & trusted devices to have SNMP access and use show SNMP host command to monitor affected systems. Moreover, administrators can also mitigate SNMP vulnerabilities by disabling following Management Information Bases:

ADSL-LINE-MIB

ALPS-MIB

CISCO-ADSL-DMT-LINE-MIB

CISCO-BSTUN-MIB

CISCO-MAC-AUTH-BYPASS-MIB

CISCO-SLB-EXT-MIB

CISCO-VOICE-DNIS-MIB

CISCO-VOICE-NUMBER-EXPANSION-MIB

TN3270E-RT-MIB

Cisco provides Cisco IOS Software Checker, the tool for the users to identify any exposure to vulnerabilities in Cisco IOS and IOS XE Software. This tool determines security advisories that impacted software release.

For the information regarding updates and official announcements, stay tuned to Digital Riser.